Implement initial chrome.browserAction.openPopup API.

chrome/common/extensions/features/complex_feature.cc

Index: chrome/common/extensions/features/complex_feature.cc
diff --git a/chrome/common/extensions/features/complex_feature.cc b/chrome/common/extensions/features/complex_feature.cc
index 57c9ad4d943bf730a22874276e5f9fd9e3580cc1..3668a5b1bade21c5e140db3cfc4204d50d27110b 100644
--- a/chrome/common/extensions/features/complex_feature.cc
+++ b/chrome/common/extensions/features/complex_feature.cc
@@ -66,8 +66,8 @@ std::set<Feature::Context>* ComplexFeature::GetContexts() {
 }
 
 bool ComplexFeature::IsInternal() const {
-  NOTREACHED();
-  return false;
+  // TODO(justinlin): Same as the above TODO.
+  return features_[0]->IsInternal();
 }
 
 std::string ComplexFeature::GetAvailabilityMessage(AvailabilityResult result,